Tires - Revision history

Juliansch24: /* Wet */

2023-01-18T21:22:52Z

Wet

Juliansch24: /* Dry */

2023-01-18T21:18:55Z

Dry

FsaeIllumina: added analysis section

2021-01-11T16:39:55Z

added analysis section

AG at 19:50, 24 May 2020

2020-05-24T19:50:26Z

AG at 19:49, 24 May 2020

2020-05-24T19:49:10Z

AG at 19:39, 24 May 2020

2020-05-24T19:39:58Z

AG: /* Theory Stuff */

2020-05-24T19:34:28Z

Theory Stuff

Bertaveira: Add to vehicle dynamics as well

2020-05-23T10:27:43Z

Add to vehicle dynamics as well

Whome: /* List of Tires */

2020-05-21T06:11:05Z

List of Tires

Whome: /* List of Tires */

2020-05-21T06:05:47Z

List of Tires

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+|
 |-
+|Goodyear
+|D2703
+|20.0x7.0-13
+|8.8LBS
+|
+|
 |}
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 =References=
 <code><references /></code>

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 |-
 |Goodyear
+| D2704<br />
+| 20.0 x 7.0-13<br />
+| 8.9LBS
+|
+|
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+|
 |}
 ==Wet==

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 =List of Tires=
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+|
 |}

@@ Line 2: / Line 2: @@
 =Theory Stuff=
 [[G-g Diagram|G-g Diagram]]
@@ Line 15: / Line 17: @@
 [[File:image34.png|center|middle|thumb|Slip angle ]]<a class="image"><img class="thumbimage" src="/images/thumb/d/db/Image34.png/300px-Image34.png" srcset="/images/thumb/d/db/Image34.png/450px-Image34.png 1.5x, /images/thumb/d/db/Image34.png/600px-Image34.png 2x" alt="" width="300" height="420" /></a> Slip angle
 As the driver steers, the slip angle rises (and so does the cornering acceleration/force), but it does not do so linearly. This is a very important aspect of tire behavior.
@@ Line 24: / Line 22: @@
 Tire Comparison (fictional)Another related aspect is “alligning torque”, which is the moment the tire exerts around its centerline to return to neutral position (pre-deformation, i.e zero slip angle). How would it generate a moment? Only if the cornering force acts at a distance from the centerline of the tire.
-[[File:Image8.png|center|middle|thumb|Pneumatic trail ]]<a class="image"><img class="thumbimage" src="/images/thumb/c/cc/Image8.png/300px-Image8.png" srcset="/images/thumb/c/cc/Image8.png/450px-Image8.png 1.5x, /images/c/cc/Image8.png 2x" alt="" width="300" height="173" /></a> Pneumatic trailNow, why is this important? Because, we are not very sensetive to accelerations - i.e, the driver cant just feel in his body that the car is at peak acceleration very accurately. As such, the feedback of the tires through the steering wheel is very useful.
+[[File:Image8.png|center|middle|thumb|Pneumatic trail ]]Now, why is this important? Because, we are not very sensetive to accelerations - i.e, the driver cant just feel in his body that the car is at peak acceleration very accurately. As such, the feedback of the tires through the steering wheel is very useful.
@@ Line 51: / Line 48: @@
 [[File:Image20.png|link=https://en.wikipedia.org/wiki/Tire_load_sensitivity|center|middle|thumb|Load Sensitivity ]]
@@ Line 63: / Line 64: @@
 =List of Tires=
 [https://www.millikenresearch.com/fsaettc.html Formula SAE Tire Test Consortium]
@@ Line 73: / Line 76: @@
 <br />
@@ Line 215: / Line 222: @@
 [[Category:Suspension]][[Category:Vehicle Dynamics]]

@@ Line 2: / Line 2: @@
 =Theory Stuff=
 [[G-g Diagram|G-g Diagram]]
@@ Line 10: / Line 14: @@
 Tires are rubber based, with metal cords to re-enforce the structure both on the contact face, and on the vertical “side walls”. They are most commonly pneumatic (i.e inflated with air), and the result is a substantially stiff rolling structure, with the rubber generating adhesion as well as mechanical “interlocking” with the asphalt, with the result being friction.Why do tires matter? Put simply, they are the only link of the car with the ground. While almost all systems are critical for the car operation, the tires have a special role in the car’s performance - a race-car generates forces and accelerations, both through driver inputs and engine power. In this way, the tires are essentially a “gate-keeper”, where the limit of force (and as such acceleration) has an upper limit. So, more engine power, or more brake power, is only helpful if the tires can handle it. Why is more acceleration better? On a race-track, better acceleration/deceleration in a straight line means higher top speed and later braking before the corner. In a corner, better acceleration means higher corner speeds for a given radius (a=v^2/r).<br />It gets more complex. The tire is not fully rigid. If it was, it would not be able to “store” energy and generate cornering force. It is best to think of it like a spring, and cornering forces generate a torsion around the vertical axis going through the tire centerpoint. The twist angle generated is called “Slip angle”.
 [[File:Image6.png|center|middle|thumb|Tire Comparison (fictional)]]
-<a class="image"><img class="thumbimage" src="/images/thumb/1/15/Image6.png/300px-Image6.png" srcset="/images/thumb/1/15/Image6.png/450px-Image6.png 1.5x, /images/thumb/1/15/Image6.png/600px-Image6.png 2x" alt="" width="300" height="343" /></a> Tire Comparison (fictional)Another related aspect is “alligning torque”, which is the moment the tire exerts around its centerline to return to neutral position (pre-deformation, i.e zero slip angle). How would it generate a moment? Only if the cornering force acts at a distance from the centerline of the tire.
+<a class="image"><img class="thumbimage" src="/images/thumb/1/15/Image6.png/300px-Image6.png" srcset="/images/thumb/1/15/Image6.png/450px-Image6.png 1.5x, /images/thumb/1/15/Image6.png/600px-Image6.png 2x" alt="" width="300" height="343" /></a> Tire Comparison (fictional)
-[[File:Image8.png|center|middle|thumb|Pneumatic trail ]]Now, why is this important? Because, we are not very sensetive to accelerations - i.e, the driver cant just feel in his body that the car is at peak acceleration very accurately. As such, the feedback of the tires through the steering wheel is very useful.
+[[File:Image8.png|center|middle|thumb|Pneumatic trail ]]<a class="image"><img class="thumbimage" src="/images/thumb/c/cc/Image8.png/300px-Image8.png" srcset="/images/thumb/c/cc/Image8.png/450px-Image8.png 1.5x, /images/c/cc/Image8.png 2x" alt="" width="300" height="173" /></a> Pneumatic trailNow, why is this important? Because, we are not very sensetive to accelerations - i.e, the driver cant just feel in his body that the car is at peak acceleration very accurately. As such, the feedback of the tires through the steering wheel is very useful.
@@ Line 31: / Line 38: @@
-Another factor is the tire’s relationship to vertical load - i.e, why heavier cars dont corner as well as lighter cars. Tires operate with both “adhesion” and “Hysteresis” that can also be called as “mechanical interlocking” on a macro scale with the asphalt. A sidenote - The adhesion is vastly reduced in the rain, but the Hysteresis is not affected.
+[[File:Image14.png|link=https://www.fhwa.dot.gov/publications/research/safety/14065/002.cfm|center|middle|thumb|Mechanisms of grip ]]
-[[File:Image14.png|link=https://www.fhwa.dot.gov/publications/research/safety/14065/002.cfm|center|middle|thumb|Mechanisms of grip ]]
+[[File:Image29.png|link=http://insideracingtechnology.com/tirebkexerpt1.htm|center|middle|thumb|Load sensitivity ]]Consequentially, the coefficient = Fcornering/Fnormal decreases, as 1 unit of Fnormal increase results in a <1 unit of Fcornering increase - contributing to the value (being a ratio) to reduce.
-Now, the coefficient of friction of the tire is unitless, and it is the single most important measure of tire performance - or at least, the easiest one to see at a glance. We were taught in highschool physics that this friction coefficient is constant, and independent of surface area. That is not true! On some materials it may stay very near constant. But on a rubber tire, the coefficient is actually negatively correlated to vertical load - load goes up, coefficient goes down. This is substantial enough to be the single biggest justification for making a race-car lighter.<br />Below, a primary reason for this behavior is seen. This is the macro level “interlocking” of the rubber with the asphalt, a very conventional friction model. As the vertical (i.e normal) load increases, the rubber expands to fill the road ridges, but it begins to saturate (i.e it cannot go any further into the asphalt).
+[[File:Image20.png|link=https://en.wikipedia.org/wiki/Tire_load_sensitivity|center|middle|thumb|Load Sensitivity ]]
@@ Line 56: / Line 63: @@
 =List of Tires=
 [https://www.millikenresearch.com/fsaettc.html Formula SAE Tire Test Consortium]
 [https://www.hoosiertire.com/tires/circuit/spec/#panel-spec Hoosier Tires FSAE 2020]
 [http://www.avonmotorsport.com/resource-centre/tyre-applications/sae-formula-student Avon Tyres Formula Student]
@@ Line 65: / Line 73: @@
 <br />
@@ Line 203: / Line 215: @@
 [[Category:Suspension]][[Category:Vehicle Dynamics]]
 =References=
 <code><references /></code>

@@ Line 11: / Line 11: @@
-<a class="image"><img alt="" src="/images/thumb/d/db/Image34.png/300px-Image34.png" decoding="async" width="300" height="420" class="thumbimage" srcset="/images/thumb/d/db/Image34.png/450px-Image34.png 1.5x, /images/thumb/d/db/Image34.png/600px-Image34.png 2x"></a>  <a class="internal" title="Enlarge"></a>Slip AngleAs the driver steers, the slip angle rises (and so does the cornering acceleration/force), but it does not do so linearly. This is a very important aspect of tire behavior.
+<a class="image"><img class="thumbimage" src="/images/thumb/d/db/Image34.png/300px-Image34.png" srcset="/images/thumb/d/db/Image34.png/450px-Image34.png 1.5x, /images/thumb/d/db/Image34.png/600px-Image34.png 2x" alt="" width="300" height="420" /></a> Slip AngleAs the driver steers, the slip angle rises (and so does the cornering acceleration/force), but it does not do so linearly. This is a very important aspect of tire behavior.
@@ Line 19: / Line 19: @@
-<a class="image"><img alt="" src="/images/thumb/1/15/Image6.png/300px-Image6.png" decoding="async" width="300" height="343" class="thumbimage" srcset="/images/thumb/1/15/Image6.png/450px-Image6.png 1.5x, /images/thumb/1/15/Image6.png/600px-Image6.png 2x"></a>  <a class="internal" title="Enlarge"></a>Tire Comparison (fictional)Another related aspect is “alligning torque”, which is the moment the tire exerts around its centerline to return to neutral position (pre-deformation, i.e zero slip angle). How would it generate a moment? Only if the cornering force acts at a distance from the centerline of the tire.
+<a class="image"><img class="thumbimage" src="/images/thumb/1/15/Image6.png/300px-Image6.png" srcset="/images/thumb/1/15/Image6.png/450px-Image6.png 1.5x, /images/thumb/1/15/Image6.png/600px-Image6.png 2x" alt="" width="300" height="343" /></a> Tire Comparison (fictional)Another related aspect is “alligning torque”, which is the moment the tire exerts around its centerline to return to neutral position (pre-deformation, i.e zero slip angle). How would it generate a moment? Only if the cornering force acts at a distance from the centerline of the tire.
@@ Line 42: / Line 42: @@
 Now, the coefficient of friction of the tire is unitless, and it is the single most important measure of tire performance - or at least, the easiest one to see at a glance. We were taught in highschool physics that this friction coefficient is constant, and independent of surface area. That is not true! On some materials it may stay very near constant. But on a rubber tire, the coefficient is actually negatively correlated to vertical load - load goes up, coefficient goes down. This is substantial enough to be the single biggest justification for making a race-car lighter.<br />Below, a primary reason for this behavior is seen. This is the macro level “interlocking” of the rubber with the asphalt, a very conventional friction model. As the vertical (i.e normal) load increases, the rubber expands to fill the road ridges, but it begins to saturate (i.e it cannot go any further into the asphalt).
 =List of Tires=

← Older revision		Revision as of 19:34, 24 May 2020
Line 8:		Line 8:


		+	Tires are rubber based, with metal cords to re-enforce the structure both on the contact face, and on the vertical “side walls”. They are most commonly pneumatic (i.e inflated with air), and the result is a substantially stiff rolling structure, with the rubber generating adhesion as well as mechanical “interlocking” with the asphalt, with the result being friction.Why do tires matter? Put simply, they are the only link of the car with the ground. While almost all systems are critical for the car operation, the tires have a special role in the car’s performance - a race-car generates forces and accelerations, both through driver inputs and engine power. In this way, the tires are essentially a “gate-keeper”, where the limit of force (and as such acceleration) has an upper limit. So, more engine power, or more brake power, is only helpful if the tires can handle it. Why is more acceleration better? On a race-track, better acceleration/deceleration in a straight line means higher top speed and later braking before the corner. In a corner, better acceleration means higher corner speeds for a given radius (a=v^2/r).<br />It gets more complex. The tire is not fully rigid. If it was, it would not be able to “store” energy and generate cornering force. It is best to think of it like a spring, and cornering forces generate a torsion around the vertical axis going through the tire centerpoint. The twist angle generated is called “Slip angle”.
		+
		+
		+	<a class="image"><img alt="" src="/images/thumb/d/db/Image34.png/300px-Image34.png" decoding="async" width="300" height="420" class="thumbimage" srcset="/images/thumb/d/db/Image34.png/450px-Image34.png 1.5x, /images/thumb/d/db/Image34.png/600px-Image34.png 2x"></a> <a class="internal" title="Enlarge"></a>Slip AngleAs the driver steers, the slip angle rises (and so does the cornering acceleration/force), but it does not do so linearly. This is a very important aspect of tire behavior.
		+
		+
		+
		+
		+	[[File:Image6.png\|center\|middle\|thumb\|Tire Comparison (fictional)]]
		+
		+
		+	<a class="image"><img alt="" src="/images/thumb/1/15/Image6.png/300px-Image6.png" decoding="async" width="300" height="343" class="thumbimage" srcset="/images/thumb/1/15/Image6.png/450px-Image6.png 1.5x, /images/thumb/1/15/Image6.png/600px-Image6.png 2x"></a> <a class="internal" title="Enlarge"></a>Tire Comparison (fictional)Another related aspect is “alligning torque”, which is the moment the tire exerts around its centerline to return to neutral position (pre-deformation, i.e zero slip angle). How would it generate a moment? Only if the cornering force acts at a distance from the centerline of the tire.
		+
		+
		+	[[File:Image8.png\|center\|middle\|thumb\|Pneumatic trail ]]Now, why is this important? Because, we are not very sensetive to accelerations - i.e, the driver cant just feel in his body that the car is at peak acceleration very accurately. As such, the feedback of the tires through the steering wheel is very useful.
		+
		+
		+	[[File:Image151.png\|link=https://www.semanticscholar.org/paper/Modeling-%2C-Analysis-and-Control-Methods-for-Vehicle-Takahashi/3f1dc5d4f82dce2e5a25cf20d470bbe68d4bb2b3\|center\|middle\|thumb]]
		+
		+
		+	This is where it should be noted that this torque is also non linear, relative to slip angle and to cornering force! What the driver would feel is increasing steering force, then gradually decreasing, while the car is still increasing in cornering force. This is due to the slippage of the contact patch changing location.
		+
		+
		+
		+
		+	Another factor is the tire’s relationship to vertical load - i.e, why heavier cars dont corner as well as lighter cars. Tires operate with both “adhesion” and “Hysteresis” that can also be called as “mechanical interlocking” on a macro scale with the asphalt. A sidenote - The adhesion is vastly reduced in the rain, but the Hysteresis is not affected.
		+
		+
		+
		+
		+	[[File:Image14.png\|link=https://www.fhwa.dot.gov/publications/research/safety/14065/002.cfm\|center\|middle\|thumb\|Mechanisms of grip ]]
		+
		+
		+	Now, the coefficient of friction of the tire is unitless, and it is the single most important measure of tire performance - or at least, the easiest one to see at a glance. We were taught in highschool physics that this friction coefficient is constant, and independent of surface area. That is not true! On some materials it may stay very near constant. But on a rubber tire, the coefficient is actually negatively correlated to vertical load - load goes up, coefficient goes down. This is substantial enough to be the single biggest justification for making a race-car lighter.<br />Below, a primary reason for this behavior is seen. This is the macro level “interlocking” of the rubber with the asphalt, a very conventional friction model. As the vertical (i.e normal) load increases, the rubber expands to fill the road ridges, but it begins to saturate (i.e it cannot go any further into the asphalt).

	=List of Tires=		=List of Tires=

← Older revision		Revision as of 06:11, 21 May 2020
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	=List of Tires=		=List of Tires=
−	[https://www.millikenresearch.com/fsaettc.html Formula SAE Tire Test Consortium]~~<br /><br />~~[https://www.hoosiertire.com/tires/circuit/spec/#panel-spec Hoosier Tires FSAE 2020]	+	[https://www.millikenresearch.com/fsaettc.html Formula SAE Tire Test Consortium]
		+
		+
		+	[https://www.hoosiertire.com/tires/circuit/spec/#panel-spec Hoosier Tires FSAE 2020]
		+
		+
		+	[http://www.avonmotorsport.com/resource-centre/tyre-applications/sae-formula-student Avon Tyres Formula Student]
		+
		+
		+	<br />
		+
		+
		+
		+